JP6132363B2 - Composite laminates with improved impact strength and uses thereof - Google Patents

Description

  The present invention relates to carbon fiber reinforced polymer composite materials, and more specifically, the present invention relates to carbon fiber reinforced polymer composite laminates having improved impact strength, methods for their preparation, and uses thereof.

  Carbon fiber reinforced polymer (CFRP) is made from high strength and high modulus carbon fiber and epoxy resin base material, with high specific strength and specific modulus (ratio of strength or modulus to density), excellent thermal stability Provides a very attractive combination of safety and good corrosion resistance, so it is widely used in transportation, sports equipment, or other fields requiring lightweight, high strength structural components. As the demand for energy consumption reduction gradually increases, the use of carbon fiber reinforced polymer materials to replace metal materials as components in lightweight vehicles, high speed trains, and even commercial aircraft, especially in the field of transportation, It has become more and more common. In societies with growing environmental awareness, it will become increasingly important to promote the application of carbon fiber reinforced polymer materials.

  With regard to the main application area of carbon fiber reinforced polymer materials, one of the important properties required is that it can maintain structural integrity even in the face of unexpected impacts or blows. Especially for the purpose of reducing weight, when considering using carbon fiber reinforced polymer material as vehicle structural component, structural component made from carbon fiber reinforced polymer is made from conventional steel or aluminum It is crucial to ensure that the same or the same conservation outcome is given as the components made. Compared to other high performance fibers (such as composites made from para-aramid fibers or glass fibers), carbon fiber reinforced polymer materials provide high specific strength and specific modulus, but relatively Providing insufficient impact strength limits the application of carbon fiber reinforced polymer materials. Today, in the composite industry, two methods are generally proposed to improve the impact strength of carbon fiber reinforced polymer materials: (1) increase the thickness of the carbon fiber reinforced polymer material but at the same time the final weight And a method of increasing the cost of the component: (2) A method of using a carbon fiber reinforced polymer material in combination with other high-performance fibers having a better impact resistance performance, which has a better impact resistance performance. A method wherein the high performance fibers include para-aramid fibers or glass fibers. However, such fiber material combinations still have the problem that the combination increases the total weight and thickness of the final product.

  Canadian Patent No. 25454981 discloses a composite laminate for use in sports equipment, the composite laminate comprising: (a) a composite material layer pre-impregnated with a plurality of fiber-containing resins as an outer layer; ) The core layer comprises a pre-impregnated fiber layer having a higher rigidity sandwiched between composite material layers pre-impregnated with a plurality of fiber-containing resins. As an outer layer, the fibers of the composite material layer pre-impregnated with resin include high-performance fibers (for example, glass fibers, Kevlar (registered trademark) fibers, Vectran (registered trademark) fibers, etc.), The fibers used as the core layer can be woven or non-woven and can be selected from high performance fibers (eg, carbon fibers, graphite fibers, or glass fibers mixed with carbon fibers). The composite laminate typically comprises 1-6 layers of the core layer (preferably a carbon fiber layer) and 4-12 layers of the outer composite material layer (preferably a glass fiber layer), The thickness of the composite laminate is usually 4 to 30 mm.

  US Pat. No. 6,995,099B1 discloses a composite of fiber reinforced polymer material, the composite material comprising: (a) a sheet-like fiber reinforced polymer material layer; and (b) a fiber reinforced polymer material layer. A fiber (for example, glass fiber, para-aramid fiber, carbon fiber (preferably carbon fiber), etc.) used for the fiber-reinforced polymer material layer comprising a non-woven layer laminated on at least one side of And having a high strength and a high elastic modulus, the layer can be a unidirectional knitted fabric, a bi-directional knitted fabric or a suture, and the fibers of the nonwoven layer are nylon 6, nylon 66, It comprises vinylon, para-aramid, polyester, polyethylene and the like. Of these fibers, nylon 6 and nylon 66 having high crystallinity are preferable. The present invention discloses three methods for integrating the layer (a) and the layer (b). The first method uses short fibers in the layer (b), and the short fibers in the layer (b) are needles, for example. This is a method in which the layer (a) is integrated with the layer (b) through the layer (a) by a punching method. The second method is to integrate the layer (a) and the layer (b) by using pressure-sensitive adhesion. The third method is to add a low melting point fiber (the content of the low melting point fiber is 5 to 50% by weight) to the layer (b) and thermally bond the low melting point fiber. In this method, layer (a) is integrated with layer (b).

  JP-A-2005-336407 discloses a composite material having excellent surface smoothness, and the composite material includes a fiber reinforced layer, a nonwoven fabric layer laminated on one or both sides of the fiber reinforced layer, and a laminate formed. The fiber used for the fiber reinforced layer can be any fiber, and carbon fiber, glass fiber and p-aromatic polyamide fiber are preferable, and the fiber used in the nonwoven fabric layer is used. The fibers may be carbon fibers, glass fibers, p-aromatic polyamide fibers, boron fibers, metal fibers, and the like. Of these fibers, carbon fibers and glass fibers are preferred. Considering the surface smoothness of the composite laminate, the nonwoven fiber layer has a thickness of 0.05 to 0.5 mm, the fiber reinforced layer has a thickness of 0.2 mm or less, and the nonwoven fiber layer and The thickness ratio of the fiber reinforced layer is 0.5 or more.

  In the currently published technical literature, the use of carbon fiber reinforced polymer materials in combination with materials such as glass fibers, graphite fibers, and aramid fibers has been addressed, but the thickness and weight of the materials remain almost unchanged. There remains a need to find composite materials that are desired to improve their impact strength.

One aspect of the present invention is a composite laminate having improved impact strength, wherein the composite laminate is the following component (a) a multilayer carbon fiber fabric, wherein the carbon fiber fabric has a bi-directional weave. A fabric that may have a unidirectional weave;
(B) a multilayer nonwoven mat, wherein the nonwoven mat is made from para-aramid;
(B) comprises or substantially comprises a cured epoxy resin,
The cured epoxy resin is made from an epoxy resin system designed for impregnation into a carbon fiber fabric layer, and at least one nonwoven mat is sandwiched between two carbon fiber fabric layers to form a composite laminate Both the outer surface layers are carbon fiber fabric layers.

  The present invention relates to the impact of a product by forming a composite laminate using a carbon fiber reinforced polymer layer and a nonwoven mat made from para-aramid without changing the weight and thickness per unit area of the final product. Significantly improves strength, bending strength and flexural modulus.

In accordance with another aspect of the present invention, a method for preparing a composite laminate having improved impact strength comprising:
(I) A step of providing a multilayer carbon fiber fabric and a multilayer nonwoven mat, wherein the carbon fiber fabric may have a bi-directional woven fabric or a unidirectional woven fabric, and the nonwoven mat -A process made from aramid;
(Ii) impregnating the carbon fiber fabric layer with an epoxy resin system designed for impregnation;
(Iii) positioning at least one impregnated carbon fiber fabric layer on the first outer surface layer;
(Iv) a step of alternately positioning at least one nonwoven mat and at least one impregnated carbon fiber fabric layer until the total thickness of the composite laminate is 0.5-30 mm, The second outer surface layer is an impregnated carbon fiber fabric layer,
(V) placing the preform obtained in step (iv) into a mold and tightening the mold;
(Vi) optionally applying a vacuum to the mold containing the preform to release bubbles remaining between the layers;
(Vii) autoclaving the preform obtained in steps (iv) and (vi) for 0.5-12 hours until the epoxy resin system designed for impregnation is cured (autoclave is 50-200) At a temperature of 0.2 to 5.0 MPa at a temperature)
(Viii) including a step of removing the preform from the mold when the temperature falls to room temperature in order to obtain a composite laminate.

  Another aspect of the present invention is to provide parts and components of a sports equipment comprising the composite laminate of the present invention, the sports equipment comprising a tennis racket, a badminton racket, a squash racket, a bicycle composite. Includes parts, baseball bats, hockey sticks, snowboards, and sleds.

  Another aspect of the present invention is to provide a product and components of a transportation means comprising the composite laminate of the present invention, the transportation means comprising a passenger car, a ship, a train, a magnetic levitation vehicle, and Includes aircraft.

It is a sectional side view of one form of the composite laminated body which concerns on this invention. It is a fragmentary sectional view of one form of a composite layered product concerning the present invention. It is a fragmentary sectional view of another form of the composite laminated body which concerns on this invention. It is a fragmentary sectional view of another form of the composite laminated body which concerns on this invention.

  Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention relates. In case of dispute, the present specification, including definitions, will be reviewed.

  All percentages, parts, ratios described herein are by weight unless otherwise specified.

  Where an amount, concentration, or other value or parameter is shown as either a range, preferred range or preferred upper limit and / or list of preferred lower limits, this is the case when the range is disclosed separately It is understood that all ranges formed from pairs of any upper range limit or preferred value and any lower range limit or preferred value, whether or not, are specifically disclosed. When numerical ranges are described herein, unless otherwise stated, the ranges are intended to include the endpoints and all integers and fractions within the ranges.

  In this specification, the term “formed by” or “consisting of” is synonymous with “comprising”. As used herein, the terms “comprising”, “comprising”, “comprising”, “comprising”, “having”, “having”, “containing” or “containing” Or other variations thereof are intended to apply to non-limiting inclusions. For example, a composition, process, method, article, or device comprising a list of elements is not necessarily limited to these elements, and is not explicitly listed; such compositions, processes, methods, It may include other elements that are not unique to the article or device. Further, unless otherwise specified, “or” means an inclusive “or” and not an exclusive “or”. For example, the condition A “or” B is satisfied by any one of the following. A is true (or present) and B is false (or nonexistent), A is false (or nonexistent) and B is true (or exists), and both A and B are true Is (or exists).

Carbon Fiber Fabric The term “carbon fiber” refers to an inorganic polymer fiber having a carbon content greater than 90%, and the carbon content of graphite fiber is greater than 99%. Carbon fiber has high strength and elastic modulus, no creep, good fatigue resistance, specific heat and conductivity between non-metal and metal, low thermal expansion coefficient, good resistance to resistance. Has corrosivity, low fiber density, and good X-ray transmission. However, carbon fibers have poor impact resistance, are easily damaged, and are oxidized in strong acids. Therefore, the carbon fiber must be surface treated before use.

  Carbon fibers may be used for rayon, pitch, phenol aldehyde, polyvinyl alcohol, polyvinyl chloride, and other fibers. In particular, in order to produce inorganic polymer fibers having high strength, high elastic modulus and high heat resistance, polyacrylonitrile (PAN) fibrils are pre-oxidized and carbonized in the atmosphere at 200 to 300 ° C. After low temperature dry distillation at 1000 to 2000 ° C. and high temperature graphitization at 2500 to 3200 ° C., a final process including surface treatment is performed.

  The term “bidirectional fabric” refers to any form of mechanical weaving known to those skilled in the art that uses continuous long filaments, this type of weaving having warps and wefts having a significant number of continuous filaments, usually , More stable than unidirectional fabrics.

  The term “unidirectional fabric” means that more than 80% continuous long fibers are arranged in parallel along the machine direction (or warp) and no continuous long fibers are arranged in the other direction (or weft) or 20 Usually refers to a fabric spun and joined with spun yarn, which is arranged in less than%. There are various ways of weaving unidirectional fabrics, including machine woven unidirectional fabrics, unidirectional weft-free fabrics and stitched unidirectional fabrics.

  FIG. 1 is a side cross-sectional view of one embodiment of a composite laminate of the present invention, wherein 1 represents a composite laminate, 2 represents a carbon fiber woven fabric layer containing a cured epoxy resin, and 3 represents a parallax. A carbon fiber woven fabric layer representing an aramid nonwoven mat and produced using a cured epoxy resin is arranged alternately with the nonwoven mat, and the two outer surface layers of the composite laminate are composed of a cured epoxy resin The produced carbon fiber woven fabric layer is contained.

  In the composite laminate of the present invention, there is no particular restriction on the weave of the carbon fiber woven fabric. 2, 3 and 4 show partial schematic views of two alternating layers in one form of a composite laminate of the present invention, where 1 represents the composite laminate and 2 contains a cured epoxy resin. Represents a carbon fiber woven fabric layer, 3 represents a para-aramid nonwoven mat, and 4 represents carbon fiber. FIG. 2 shows that the carbon fiber woven fabric is a unidirectional weft-free fabric, and FIGS. 3 and 4 show that the carbon woven fabric is two common non-crimp unidirectional fabrics. Show.

  In some forms of the invention, the carbon fiber fabric layer has a thickness of about 0.01 to 1.0 mm, or even about 0.05 to 0.5 mm.

  The tensile strength of the carbon fiber woven fabric used in the present invention is in the range of about 1000 to 8000 MPa, and the tensile strength in the range of about 2000 to 5000 MPa is preferable. The range of the tensile elastic modulus is about 100 to 800 GPa, preferably about 200 to 400 GPa.

  When the carbon fiber woven fabric is a bi-directional woven fabric, the arrangement of the layers of the carbon fiber fabric may be the same or different. When the carbon fiber woven fabric is a unidirectional fabric, the warp direction of the carbon fiber in each layer of the carbon fiber fabric layer may be the same (0 degree) or different (for example, 90 degrees, +45 degrees, -45 degrees, etc.). Each of the carbon fiber woven fabric layers is preferably the same in the warp direction.

Nonwoven Mat The term “para-aramid” refers to a linear polymer assembled by linking para-aromatic groups with amide or imide bonds, where at least 85% of the amide or imide bonds are directly linked to the aromatic ring. When linked and imide bonds are present, the imide bonds do not exceed the number of amide bonds.

  Examples of commercially available para-aramids are described in E.I. I. A Kevlar® product manufactured by, but not limited to, Du Pont de Nemours and Company Wilmington, DE (DuPont).

  The term “nonwoven mat” refers to a fabric that does not spin or weave fibers, is free of warp or weft, is light on average, and can be easily shaped. Fibers or long filaments are oriented or randomly oriented on struts to form a fiber network structure, which is then reinforced by mechanical bonding, thermal bonding or chemical methods to produce a product. Nonwoven products based on can be classified as spunlace, heat seal, airlaid, wet laid, spunbond, meltblown, needlework, stitchbond, and the like.

  In some forms of the invention, the nonwoven mat in the composition of the invention refers to a thin layer formed by para-aramid staple fibers by methods known to those skilled in the art in the nonwoven process, Processes include, but are not limited to, heating, entanglement, stitching and / or pressure application, etc., to form a mesh or fluff using, for example, para-aramid staple fibers.

  In the composite laminate of the present invention, the number of para-aramid nonwoven mats is not particularly limited. In some forms of the invention, the para-aramid nonwoven mat in the composite laminate of the invention is 5 to 35 layers or even 10 to 25 layers.

  In some forms of the invention, the thickness of the para-aramid nonwoven mat used in the invention is from 0.005 mm to 0.10 mm or even from 0.01 mm to 0.05 mm.

In the composite laminate of the present invention, the weight per unit area of each nonwoven mat layer may be the same or different. In some forms of the invention, the weight per unit area of the individual nonwoven mat is 5 to 40 g / m ² or even 8 to 20 g / m ² .

Epoxy resin system for impregnation applications The composition laminate of the present invention contains a cured epoxy resin. The cured epoxy resin is produced by impregnating the carbon fiber woven fabric layer with an epoxy resin system and then curing. Said epoxy resin system for impregnation refers to a curing system by adding curing agents, accelerators, fillers and other auxiliary materials to the epoxy resin, which is liquid under ambient or heated conditions. The epoxy resin generally refers to a resin containing an epoxy group, and is mainly obtained by polycondensation of epichlorohydrin and phenols (eg, bisphenol A).

  Examples of the epoxy resin used include bisphenol type epoxy resin, epoxy alcohol, hydrogenated phthalic acid type epoxy resin, dimer epoxy resin, glycidylamino group-containing epoxy resin, alicyclic epoxy resin, and phenol novolac type epoxy. Resins, cresol novolac type epoxy resins, and novolac epoxy resins may be included. Furthermore, various modified epoxy resins (eg, urethane-modified epoxy resin and rubber-modified epoxy resin) can be used.

  The present invention preferably uses a bisphenol type epoxy resin, an alicyclic epoxy resin, an epoxy resin containing a glycidylamino group, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a urethane-modified epoxy resin.

  Examples of bisphenol type epoxy resins include bisphenol A type resins, bisphenol F type resins, bisphenol AD type resins, and bisphenol S type resins. As a more specific form, commercially available epoxy resins such as EP815, EP828, EP834, EP1001, and EP807 (manufactured by Yuka Shell Epoxy Co., Ltd.), Epomik R-710 (manufactured by Mitsui Petrochemical) and EXA 1514 (made by DIC) is mentioned.

  Examples of the alicyclic epoxy resin include commercially available resins such as Araldite CY-179, CY-178, CY-182 and CY-183 (manufactured by HUNTSMAN).

  Examples of epoxy resins containing glycidylamino include MY-720 by Nippon Ciba-Geigy Co., Ltd., Epototo YH434 by Toto Kasei Co., Ltd., EP604 by Yuka Shell Epoxy Co., Ltd., ELM-120 and ELM-100 by Sumitomo Chemical Co., Ltd., and Examples include commercially available resins such as GAN manufactured by Nippon Kayaku Co., Ltd.

  Examples of phenol novolac type epoxy resins include EP152 and EP154 by Yuka Shell Epoxy Co., Ltd., DEN431, DEN485 and DEN438 by Dow Chemical, and EPICLON N740 by Dainippon Ink & Chemicals, Inc.

  Examples of cresol novolac type epoxy resins include ECN1235, ECN1273 and ECN1280 by HUNTSMAN, and EOCN102, EOCN103 and EOCN104 by Nippon Kayaku Co., Ltd.

  Furthermore, examples of urethane-modified bisphenol A type epoxy resins include Adeka Resin EPU-6 and EPU-4 by Asahi Denka Kogyo Co., Ltd.

  These epoxy resins may be used individually or in combination of two or more. Among them, bifunctional epoxy resins (eg, bisphenol type epoxy resins) may exist in different stages of products ranging from liquid to solid depending on their molecular weight. By appropriately combining the different stages of the bisphenol type epoxy resin, the final viscosity of the impregnated epoxy system can be adjusted.

  In the composition laminate of the present invention, the carbon fiber woven fabric layer is immersed in an epoxy resin system for impregnation applications to form an impregnated carbon fiber fabric layer. The impregnation refers to an epoxy resin system that is uniformly or partially immersed in the carbon fiber woven fabric layer, and the epoxy resin system for impregnation is immersed in either the entire thickness or a part of the carbon fiber fabric layer. Can be done.

  Based on the total weight of the impregnated carbon fiber fabric layer, the impregnating epoxy resin system may comprise 10 to 80 wt%, or even 20 to 70 wt%, or even 30 to 45 wt%.

  The impregnated carbon fiber fabric layer in the composite laminate of the present invention can be obtained by impregnating one or more epoxy resin systems with a carbon fiber woven fabric layer as described above. It is also possible to purchase an impregnated carbon fiber fabric layer directly, which is commonly referred to as a prepreg. The prepreg can omit two steps including preparation of an impregnation epoxy resin system and impregnation of a carbon fiber fabric layer, which is an alternative material that can save time.

In another form of the invention, the composite laminate described above comprises the following ingredients, or is basically constituted by the following components, or prepared by the following mixture:
Multi-layer prepreg layer (comprising carbon fibers impregnated with epoxy resin); the carbon fiber woven fabric described above is either a bi-directional fabric or a unidirectional fabric.
Multilayer nonwoven mat (made from polyparaphenylene terephthalamide); at least one layer of nonwoven mat is sandwiched between two prepreg layers, and the two outer surface layers of the composite laminate are the prepreg layers It is.

  In the present invention, the above-described epoxy resin system used for impregnation is first impregnated into the carbon fiber fabric layer, and then the carbon fiber fabric layer impregnated with the epoxy resin is applied after the nonwoven mat is laminated. And cured to be included in the composite laminate.

  In the composite laminate described in the present invention, the thickness of each of the impregnated carbon fiber fabric layer or prepreg layer may be the same or different. In some forms of the invention, each layer of impregnated carbon fiber fabric layer or prepreg layer is independent. The thickness of each impregnated carbon fiber fabric layer or prepreg layer is about 0.001 to 1.00 mm or even about 0.05 to 0.5 mm.

In the composite laminate described in the present invention, the weight of each layer of the impregnated carbon fiber fabric layer or prepreg layer may be the same or different. In some forms of the invention, each layer of impregnated carbon fiber fabric layer or prepreg layer is independent. The weight per unit area of each impregnated carbon fiber fabric layer or prepreg layer is about 50-660 g / m ² , or even about 80-300 g / m ² , or even about 90-200 g / m ² . .

  In the composite laminate described in the present invention, there is no limit to the number of layers with respect to the impregnated carbon fiber fabric layer or prepreg layer. In some forms of the invention, the number of impregnated carbon fiber fabric layers or prepreg layers in the composite laminate is about 10 to 40 layers, preferably 15 to 30 layers.

  The composite laminate can include an alternating arrangement of single-layer carbon fiber fabric layers and single-layer nonwoven mats. Alternate arrangements of multilayer carbon fiber fabric layers and single-layer nonwoven mats, or alternating arrangements of single-layer carbon fiber fabric layers and multilayer nonwoven mats may also be included. Alternate arrangements of a multilayer carbon fiber fabric layer and a nonwoven mat of at least one layer disposed between two layers of the carbon fiber fabric layer may also be included. Both outer layers of such a composite laminate are preferably prepreg layers. In this case, the “carbon fiber woven fabric layer” corresponds to an “impregnated carbon fiber fabric layer” or a “prepreg layer”.

  In some forms of the invention, the total weight of the composite laminate is distributed as follows: the carbon fiber woven layer and the impregnating epoxy resin comprise 85-95%, preferably 90-95%; The polyparaphenylene terephthalamide multilayer nonwoven mat comprises 5-15%, preferably 5-10% of the total weight.

  In some forms of the invention, the ratio of the thickness of the polyparaphenylene terephthalamide multilayer nonwoven mat to the cured epoxy resin layer is 0.2 or less.

The present invention also provides
(I) providing a multilayer carbon fiber fabric layer and a multilayer nonwoven mat, the multilayer carbon fiber fabric having bi-directional or unidirectional fibers, wherein the multilayer nonwoven mat is made from polyparaphenylene terephthalamide; ,
(Ii) immersing with an epoxy resin system impregnating the multilayer carbon fiber fabric layer to obtain an impregnated carbon fiber woven fabric layer;
(Iii) positioning at least one impregnated carbon fiber fabric layer as a first outer surface layer;
(Iv) alternately positioning at least one nonwoven mat and at least one impregnated carbon fiber fabric layer until the total thickness of the composite laminate reaches 0.5-30 mm; The second outer surface layer is also an impregnated carbon fiber fabric layer to make a preform;
(V) placing the preform obtained in step (iv) into a mold and tightening the mold;
(Vi) optionally subjecting the preform to reduced pressure to release bubbles remaining in the inner layer;
(Vii) Autoclaving the preform in step (v) or step (iv) at 50 to 200 ° C. and 0.2 to 5.0 MPa for 0.5 to 12 hours until the impregnated epoxy resin system is cured When,
(Viii) peeling the composite laminate induced when the temperature is lowered to room temperature;
A method of making a composite laminate having improved impact resistance is also provided.

  With respect to step (vii) in the method of making a composite laminate with improved impact resistance, the temperature can be 50-200 ° C. or 80-150 ° C. for the thermal pressure treatment, and the pressure for the thermal pressure treatment Can be 0.2-5.0 MPa or 0.5-2.5 MPa.

  The present invention uses a composite laminate formed by a non-woven mat of suitable aromatic polyamide composition and a carbon fiber reinforced prepreg layer, and the impact strength of the final product remains almost unchanged. Improved.

  Compared to other carbon fiber reinforced polymer laminates made from para-aramid compositions (not including the present invention), the composite layer of the composition of the present invention (ie, with the same layer thickness and unit weight) (ie, The non-woven mat was sandwiched between carbon fiber fabric layers impregnated with an epoxy resin system and cured with the epoxy resin compound), and the impact strength was significantly improved by 20 to 45%, and the bending strength was 3 to 3. Increased by 11.7% and flexural modulus increased by 3 to 7.1%.

  Furthermore, the composite laminate of the present invention can be treated in the same manner as normal carbon fiber prepreg thermoforming or other processing. The description of the various aspects of the invention described herein is not only suitable for the composite laminate, but also any combination and variety suitable for the method of preparing the composite laminate and its manufactured parts. It can be implemented in the form.

  The invention will now be described in more detail by way of examples. It should be noted that the materials of the invention, the methods and forms described in the following examples are for illustrative purposes only and are not limiting.

Materials a) Unidirectional carbon fiber fabric prepreg Purchased from WuXi Tiannio Composites Company. The weight per unit area is 185 g / m ² (including 120 g / m ² carbon fiber unidirectional fabric). The carbon fiber has a bulk density of 1.8 g / cm ³ and a thickness of 0.067 mm. The unidirectional fabric is impregnated with an epoxy resin system.
b) Made from short Kevlar® fibers by preparation with para-aromatic polyamide nonwoven mat chemical method, weight per unit area is 15 g / cm ² . The nonwoven mat has a bulk density of 1.8 g / cm ³ and a thickness of 0.01 mm.
c) Nylon Nonwoven Mat Made from short nylon fibers (manufactured by WuXi Belt Rubber Belts Co., Ltd.) by manual placement SYSTEM 13NTD81835 to make a nonwoven mat. The nonwoven mat has a weight per unit area of 15 g / m ² , a bulk density of 1.14 g / cm ³ , and a thickness of 0.01 mm.

Test Method Based on GB / T3356-99, the bending strength and bending elastic modulus of the laminate samples of the examples and comparative examples were tested.

  Using the Resil Impactor instrument according to the standard in ISO 179, the average unnotched Charpy impact strength of the laminate samples of the examples and comparative examples was determined.

Comparative Example 1
A pre-impregnated sheet of unidirectional carbon fibers having a weight per unit area of 185 g / m ² is cut into approximately 300 mm × 300 mm sheets and 14 according to the same fiber orientation (meridian) to prepare a laminated preform. This pre-impregnated sheet of layers was stacked together. The preform was placed on a flat aluminum mold, then the mold was transferred to a press preheated to 130 ° C., the mold was clamped (ie, clamped by a clamping mechanism), and a pressure of 1.0 MPa was applied to the mold. After maintaining the laminated preform at 130 ° C. for 1 hour, the heat treatment was stopped and the sample was cooled to room temperature. The carbon fiber reinforced polymer laminate was removed from the mold and the final thickness of the laminate was measured to be 1.746 mm.

Example 1
A pre-impregnated sheet of unidirectional carbon fibers having a weight per unit area of 185 g / m ² was cut into approximately 300 mm × 300 mm sheets. A Kevlar® non-woven mat having a weight per unit area of 15 g / m ² was similarly cut into approximately 300 mm × 300 mm sheets. After first placing one layer of pre-impregnated sheet (ie, impregnated carbon fiber fabric layer) as the surface of the first outer layer, two sheets of sheet pre-impregnated with Kevlar® non-woven mat The non-woven mat layer and the other layer of the pre-impregnated sheet were alternately arranged so as to be sandwiched between the layers. A total of 12 sheets were prepared to stack each pre-impregnated sheet together according to the same fiber orientation (meridian) to prepare a composite laminate preform consisting of Kevlar® non-woven mat and carbon fiber reinforced polymer. A pre-impregnated sheet layer and a total of 11 Kevlar® non-woven mat layers were used. The preform was placed on a flat aluminum mold, then the mold was transferred to a press preheated to 130 ° C., the mold was clamped (ie, clamped by a clamping mechanism), and a pressure of 1.0 MPa was applied to the mold. After maintaining the preform at 130 ° C. for 1 hour, the heat treatment was stopped and the sample was cooled to room temperature. A composite laminate preform composed of Kevlar® non-woven mat and carbon fiber reinforced polymer was removed from the mold and the final thickness of the laminate was measured to be 1.742 mm.

Comparative Example 2
Using a method similar to that of Comparative Example 1, a pre-impregnated sheet of 31 layers of carbon fiber having a size of 150 mm x 150 mm was measured as a carbon fiber reinforced polymer laminate (final thickness was 3.674 mm). Was used in the preparation of

Example 2
Using a method similar to that of Example 1, for the preparation of a carbon fiber reinforced polymer composite laminate (whose final thickness is measured to be 3.662 mm), 26 layers having a size of 150 mm × 150 mm A pre-impregnated sheet of carbon fiber and 25 layers of Kevlar® non-woven mat having a size of 150 mm × 150 mm were used. Non-woven mat so that one layer of pre-impregnated sheet is initially placed as the surface of the first outer layer and then Kevlar® non-woven mat is sandwiched between two layers of pre-impregnated sheet Layers and pre-impregnated sheet layers were alternately arranged. Each pre-impregnated sheet was stacked together according to the same fiber orientation (meridian).

Comparative Example 3
Using a method similar to that of Example 2, for the preparation of a carbon fiber reinforced polymer composite laminate (whose final thickness is measured to be 3.709 mm), 26 layers having a size of 150 mm × 150 mm are prepared. A pre-impregnated sheet of carbon fibers and a 25 layer nylon nonwoven mat having a size of 150 mm x 150 mm were used. Pre-impregnated with the non-woven mat layer so that one layer of the pre-impregnated sheet is initially placed as the surface of the first outer layer and then the nylon non-woven mat is sandwiched between the two layers of the pre-impregnated sheet The laminated sheet layers were alternately arranged. Each pre-impregnated sheet was stacked together according to the same fiber orientation.

Sample Tests a) Laminate samples (length 300 mm, width 300 mm, thickness 1.746 mm and 1.742 mm, respectively) obtained from Comparative Example 1 and Example 1 were tested for flexural strength and flexural modulus.
b) Laminate samples obtained from Comparative Example 2, Comparative Example 3 and Example 3 (length 150 mm, width 150 mm, thicknesses 3.674 mm, 3.709 mm and 3.662 mm, respectively) were tested for impact strength.

  The results of these tests are shown in Tables 1 and 2.

  From the above test results, it can be seen that the addition of para-aramid nonwoven mat effectively improved the flexural strength and flexural modulus of the carbon fiber reinforced polymer composite laminate having the same thickness. The thicknesses and measured weights of Example 1 and Comparative Example 1 are substantially the same, but compared with the sample of Comparative Example 1, the bending strength of the sample of Example 1 is improved by 11.7% and flexural elasticity is increased. The rate has improved by 7.1%.

  From the impact strength test results, it can be seen that the impact strength of the carbon fiber reinforced polymer composite laminate was effectively improved by adding the para-aramid nonwoven mat. Example 2 and Comparative Example 2 had similar weight and thickness, but the impact strength of Example 2 was increased by 45.3% compared to Comparative Example 2. Furthermore, when compared with Comparative Example 2, the fact that Example 2 used only a 26 layer pre-impregnated sheet of carbon fiber meant that 16.1% of the pre-impregnated sheet of carbon fiber was reduced. Surprisingly, it was found that the impact strength was improved unexpectedly.

  Furthermore, Example 2 and Comparative Example 3 had similar weight and thickness, but the impact strength of Example 2 was increased by 10% compared to Comparative Example 3. This shows that the impact strength of the carbon fiber reinforced polymer composite laminate was effectively improved by using a para-aramid nonwoven mat as compared to a nylon nonwoven mat having a similar weight and thickness.

Although the present invention has been described in detail on the basis of representative forms, the present invention is not limited to these examples, and may be appropriately modified without departing from the scope of the present invention. Accordingly, those skilled in the art will appreciate that various modifications and equivalent embodiments may be made in these forms, and that various modifications and equivalent embodiments do not depart from the scope of the invention.
Another aspect of the present invention may be as follows.
[1] A composite laminate having improved impact strength,
(A) a multilayer carbon fiber fabric, wherein the carbon fiber fabric may be a bi-directional woven fabric or a unidirectional woven fabric;
(B) a multilayer nonwoven mat, wherein the nonwoven mat is made from para-aramid;
(C) comprising a cured epoxy resin,
The cured epoxy resin is made from an epoxy resin system designed for impregnation in which the carbon fiber fabric layer is impregnated, and at least one layer of the nonwoven mat is sandwiched between two layers of carbon fiber fabric layers. Composite laminate.
[2] The composite laminate according to [1], wherein the composite laminate has a total thickness of 0.5 mm to 30 mm, or 1.0 mm to 10 mm, or 1.5 mm to 5 mm.
[3] The total weight of the carbon fiber fabric layer and the cured epoxy resin is 85 to 95% of the total weight of the composite laminate, and the weight of the multilayer nonwoven mat is the total weight of the composite laminate. The composite laminate according to [1], which is 5 to 15%.
[4] The epoxy resin-based epoxy resin designed for impregnation is a bisphenol type epoxy resin, an alicyclic epoxy resin, an epoxy resin containing glycidyl and amino groups, a phenol novolac type epoxy resin, a benzcresol novolac type epoxy The composite laminate according to [1], selected from the group consisting of a resin and a urethane-modified epoxy resin.
[5] a weight per unit area of each layer of the impregnated carbon fiber fabric layers, independently, the representative of the 50~660g / m ² or 80~300g / m ² or 90 to 200 g / m ^2, [1 ] The composite laminated body as described in above.
[6] The weight of the epoxy resin system designed for impregnation is 10 to 80%, or 20 to 70%, or 30 to 45% of the total weight of the impregnated carbon fiber fabric layer [1] The composite laminate according to 1.
[7] The composite laminate according to [1], wherein the weight per unit area of each layer of the nonwoven mat independently represents ⁵ to 40 g / m ² , or 8 to 20 g / m ² .
[8] A method of preparing a composite laminate having improved impact strength,
(I) A step of preparing a multilayer carbon fiber fabric and a multilayer nonwoven mat, wherein the carbon fiber fabric may be bi-directional or unidirectional, and the nonwoven mat is para-aramid. A process made from
(Ii) impregnating the carbon fiber fabric layer with an epoxy resin system designed for impregnation;
(Iii) positioning at least one impregnated carbon fiber fabric layer as a first outer surface layer;
(Iv) impregnated with at least one non-woven mat and at least one layer as a second outer surface layer to form a preform until the total thickness of the composite laminate is 0.5-30 mm Alternately positioning the carbon fiber fabric layers;
(V) putting the preform obtained in step (iv) into a mold and fastening the mold;
(Vi) optionally subjecting the mold containing the preform to a reduced pressure to release any remaining bubbles between the layers;
(Vii) autoclaving the preform obtained in steps (iv) and (vi) for 0.5-12 hours until the epoxy resin system designed for impregnation is cured (autoclave is 50- Rated at 0.2 to 5.0 MPa at 200 ° C.)
(Viii) removing the preform from the mold when the temperature is lowered to room temperature to obtain the composite laminate;
A method comprising:
[9] The composite laminate according to [1] used for parts and components of a sports equipment, wherein the sports equipment includes a tennis racket, a badminton racket, a squash racket, a bicycle composite part, and a baseball bat. Composite laminates, including hockey sticks, snowboards and sleds.
[10] The composite laminate according to [1] used for a product and a component of a transportation means, wherein the transportation means includes a passenger car, a ship, a train, a magnetic levitation vehicle, and an aircraft. body.
[11] Use of the composite laminate according to [1] in the preparation of sports equipment, wherein the sports equipment is a tennis racket, badminton racket, squash racket, bicycle composite part, baseball bat, hockey stick Use of composite laminates, including snowboards and sleds.
[12] Use of the composite laminate according to [1] in the preparation of products and components of a transportation means, wherein the transportation means includes a passenger car, a ship, a train, a magnetically levitated vehicle, and an aircraft. Use of laminates.

Claims (4)

A composite laminate having improved impact strength,
(A) a multilayer carbon fiber fabric, wherein the carbon fiber fabric may be a bi-directional woven fabric or a unidirectional woven fabric;
(B) a multilayer nonwoven mat, wherein the nonwoven mat is made from para-aramid;
(C) comprising a cured epoxy resin,
The cured epoxy resin is made from an epoxy resin system designed for impregnation in which the carbon fiber fabric layer is impregnated, and at least one layer of the nonwoven mat is sandwiched between two layers of carbon fiber fabric layers. Composite laminate. A method of preparing a composite laminate having improved impact strength,
(I) A step of preparing a multilayer carbon fiber fabric and a multilayer nonwoven mat, wherein the carbon fiber fabric may be bi-directional or unidirectional, and the nonwoven mat is para-aramid. A process made from
(Ii) impregnating the carbon fiber fabric layer with an epoxy resin system designed for impregnation;
(Iii) positioning at least one impregnated carbon fiber fabric layer as a first outer surface layer;
(Iv) impregnated with at least one non-woven mat and at least one layer as a second outer surface layer to form a preform until the total thickness of the composite laminate is 0.5-30 mm Alternately positioning the carbon fiber fabric layers;
(V) putting the preform obtained in step (iv) into a mold and fastening the mold;
Over vacuum to the mold containing (vi) pre-Symbol preform, a step may be to release the air bubbles remaining between the layers,
(Vii) autoclaving the preform obtained in steps (iv) and (vi) for 0.5-12 hours until the epoxy resin system designed for impregnation is cured (autoclave is 50- Rated at 0.2 to 5.0 MPa at 200 ° C.)
(Viii) a step of removing the preform from the mold when the temperature falls to room temperature in order to obtain the composite laminate.   Use of the composite laminate of claim 1 in the preparation of sports equipment, wherein the sports equipment is a tennis racket, badminton racket, squash racket, bicycle composite part, baseball bat, hockey stick, snowboard and sled. Use of a composite laminate comprising   Use of a composite laminate according to claim 1 in the preparation of products and components of a vehicle, wherein the vehicle comprises a passenger car, a ship, a train, a magnetically levitated vehicle, and an aircraft. .

Images